Internal combustion engine with reciprocatory piston and camshaft above the cylinder

ABSTRACT

A reciprocatory piston-operated internal combustion engine with cylinder means having associated therewith two valves in which the distance of one valve shank from the rocker shaft is greater than the distance of the other valve shank from the rocker shaft while that cam which actuates the closest valve is in the longitudinal direction of the cam shaft offset to such an extent that it is located laterally of and clears the valve spring for the respective adjacent valve.

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority Bernhard Medenus Bensberg-Lustheide, Germany INTERNAL COMBUSTION ENGINE WITH RECIPROCATORY PISTON AND CAMSIIAFT [56] References Cited UNITED STATES PATENTS 3,482,555 12/1969 sh nnin III et 1. 123/90 Primary Examiner-Al Lawrence Smith Attorney-Walter Becker g F i P ABSTRACT: A reciprocatory piston-operated internal comrawmg bustion engine with cylinder means having associated (1.8. CI. 123490.27, therewith two valves in which the distance of one valve shank l23/90.44, l23/90.65 from the rocker shaft is greater than the distance of the other Int. Cl F011 ]/00, valve shank from the rocker shaft while that cam which actu- F0ll 3/10, F011 l/l4 ates the closest valve is in the longitudinal direction ofthe cam Field of Search 123/90, 188 shaft offset to such an extent that it is located laterally of and (SC), (S), 191-0 clears the valve spring for the respective adjacent valve.

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N 7 H 3 m c Avra or- INTERNAL COMBUSTION ENGINE WITII RECIPROCATORY PISTON AND CAMSIIAFT ABOVE THE CYLINDER The present invention concerns an internal combustion engine with reciprocatory piston and with two valves per cylinder and also with a camshaft above the cylinder and angle-shaped rockers journaled on a common shaft for actuating the valves, while the camshaft islocated between the valve springs and a plane extending through the axis of the rocker shaft and parallel to the valve springs. In connection with modern internal combustion engines the requirement has to be met that the structural volume and the expenses for the structure of the internal combustion engine are kept to a minimum.

It is an object of the present invention to meet this requirement by improving heretofore-known valve drives.

This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a section through a portion of the cylinder head of an internal combustion engineaccording to the invention, said section being taken along the line H of FIG. 2.

FIG. 2 is a view of the cylinder head as seen in the direction of the arrow II of FIG. 1.

The internal combustion engine according to the present invention is characterized primarily in that the distance of one valve shank from the rocker shaft is greater than the distance of the other valve shank from said rocker shaft, and is furthermore characterized in that the cam actuating that valve which is closest thereto is offset in the longitudinal direction of the camshaft to such an extent that it is located laterally of the valve spring of the respective adjacent valve while clearing the last-mentioned valve spring.

The above arrangement according to the invention of the valve drive brings about the advantage that the camshaft can be arranged closer to the valves than has heretofore been customary. The offsetting of the cam can be bridged by means of a cranked rocker or by means of a rocker the rocker arms of which define with the longitudinal axis of the rocker shaft an acute angle. By differently guiding the two angle-shaped rockers, the influence of the location of the valves in two different longitudinal planes of the internal combustion engine can be equalized and the valve strokes can be adapted to the required conditions of operation.

Referring now to the drawings in detail, the portion of the internal combustion engine according to the invention shown therein comprises a cylinder head 1 with passages 2 for the gas change which are controlled by valves 3 and 4 respectively. The valves 3 and 4 are held in closed position by valve springs 5 and 6 respectively which rest against the cylinder head I and through spring keepers 7 and S against valve shanks 9 and 10. The valves 3, 4 are actuated by-angle-shaped rockers 11 and 12 respectively which are journaled on a common rocker shaft 13. The rocker shaft 13 extends parallel to the longitudinal axis of the engine. Between the valvesprings 5 and 6 and a plane which is parallel thereto and extends through the axis of the rocker shaft 13, there is provided a cam shaft 141 which is adapted to actuate the rockers 11 and 12 by means of cams 15 and 16. The cam 16 is in the longitudinal direction of the cam shaft 14 offset to such an extent that it laterally clears the valve spring 6 of the respective adjacent valve 4. To this end, camshaft I4 is adjacent valve spring 6 provided with a recess 14a having a contour corresponding to the circumferential contour of spring 6. While both rocker arms of the rocker 11 are located in one plane, the rocker arm of rocker 12 for actuating the valve 4 is arranged at an angle with regard to the direction of movement of the other rocker arm (FIG. 2),

whereby the offsetting in the longitudinal direction of the cam 16 will be bridged. This bridging may also be obtained by cranking the rocker within the region where it is journaled on the rocker shaft. As will be evident from FIG. 1, the rockers l1 and 12 are of different design. In connection with the design of the earns 15 and 16, it is possible in this way to compensate for the different transmission ratio of the rockers 11 and 12 as it is caused by the different valve distances from the rocker shaft, and to adapt the said different valve distances to the conditions of operation.

If it is desired to move the cam shaft still closer to the valves, it may be advisable to provide the camshaft, as far as its strength and bending resistance will, permit, with a recess or the like within the area of the valve spring 6.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawings but also comprises any modifications within the scope of the appended claims.

Iclaim:

1. An internal combustion engine having a cylinder with two valves for respectively controlling the inlet of a fuel-air mixture into and the exhaust of combustion gases from said cylinder, each of said valves having a valve shank, which includes: a rocker shaft, first and second rocker means supported by said rocker shaft and pivotable about the axis thereof for respectively actuating said valves, spring means respectively associated with said valves and continuously urging the same to the closing position thereof, and a camshaft having cams for respectively actuating said rocker means, said camshaft being arranged between said spring means on one hand and a plane on the other hand which plane extends through the axis of said rocker shaft and parallel to the axes of said spring means, the arrangement being such that the distance of one of said valve shanks from said rocker shaft is greater than the distance of the other valve shank from said rocker shaft, and the respective cam for actuating the respective valve closest to said cam shaft being displaced in the longitudinal direction of said cam shaft to such an extent that it is located laterally of and clears the valve spring pertaining to the respective adjacent valve.

2. An internal combustion engine according to claim I, in which said cam shaft is within the region of the spring means pertaining to the valve closest to said cam shaft provided with a recess corresponding to the circumferential contour of said last-mentioned spring means. 

1. An internal combustion engine having a cylinder with two valves for respectively controlling the inlet of a fuel-air mixture into and the exhaust of combustion gases from said cylinder, each of said valves having a valve shank, which includes: a rocker shaft, first and second rocker means supported by said rocker shaft and pivotable about the axis thereof for respectively actuating said valves, spring means respectively associated with said valves and continuously urging the same to the closing position thereof, and a camshaft having cams for respectively actuating said rocker means, said camshaft being arranged between said spring means on one hand and a plane on the other hand which plane extends through the axis of said rocker shaft and parallel to the axes of said spring means, the arrangement being such that the distance of one of said valve shanks from said rocker shaft is greater than the distance of the other valve shank from said rocker shaft, and the respective cam for actuating the respective valve closest to said cam shaft being displaced in the longitudinal direction of said cam shaft to such an extent that it is located laterally of and clears the valve spring pertaining to the respective adjacent valve.
 2. An internal combustion engine according to claim 1, in which said cam shaft is within the region of the spring means pertaining to the valve closest to said cam shaft provided with a recess corresponding to the circumferential contour of said last-mentioned spring means. 